1. Field of the Invention
This invention relates to portable torches, and more particularly to an effective technique applied to a portable torch in which a relatively fine and stable flame is required.
2. Related Art Statement
As a portable torch used in applications such as fine soldering and welding works in the chasing, where a working space is small and relatively fine flame is needed, one having the following construction is thought of.
Namely, a combustible gas and a combustion supporting gas are regulated to given values of pressure, respectively, in gas pressure regulating mechanisms mounted onto a combustible gas tank and a combustion supporting gas tank, both of which are small in size, and introduced to a torch through hoses. Control of flow rates, feedings and flow stoppage of both gases to a jet or nozzle provided at the forward end of the torch, is effected by a flow rate regulating mechanism provided in this torch.
Now, in the portable torch having the above-described construction, the pressure regulating mechanism and the flow rate regulating mechanism are provided separately of each other, whereby such a problem is presented that, for example, if the flow rate of the combustible gas and the combustion supporting gas are reduced in the flow rate regulating mechanism provided on the torch, fluctuations in feeding pressure occur in the pressure regulating mechanisms provided at the upstream side, the flow rates of the gases at the jet become unstable, and the fine flame is difficult to stabilize.
Further, in the use, both of gas on-off valves, or the pressure regulating mechanisms, and the flow rate regulating mechanism should be regulated, whereby the operations become complicated. And, the flow rate regulating mechanism is provided on the torch, whereby such a problem is presented that, in the relatively small-sized torch used in a small working space, a knob of the flow rate regulating mechanism interferes with gripping, whereby controllability of the torch is impaired.
Furthermore, as a portable torch having another construction, there is one including a torch body provided thereon with a gas tank and a torch portion where a flame is formed by a gas fed from the gas bomb through a gas pressure regulating mechanism, said torch portion having no gas flow rate regulating mechanism.
However, when a relatively fine flame is formed stably by the latter portable torch, since the torch portion has no gas flow rate regulating mechanism, a gas from a high pressure gas tank should be considerably reduced in gas pressure to be fed to the torch portion.
Since the aforesaid portable torch requires an action of reducing gas pressure to a considerable extent by the gas pressure regulating mechanism as described above, such problems are presented that the gas pressure regulating mechanism should be rendered large in size and high in precision.